kernel: implement DUP_SEARCH (like unix's F_DUPFD)

5 files changed, 24 insertions, 11 deletions

diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index 108a006..ecbd839 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -484,6 +484,9 @@ Proc *proc_next(Proc *p, Proc *root) {
 }
 
 hid_t proc_find_free_handle(Proc *proc, hid_t start_at) {
+	if (start_at < 0) {
+		start_at = 0;
+	}
 	for (hid_t hid = start_at; hid < HANDLE_MAX; hid++) {
 		if (proc->_handles[hid] == NULL)
 			return hid;
@@ -526,11 +529,11 @@ hid_t proc_handle_init(Proc *p, enum handle_type type, Handle **hs) {
 	return hid;
 }
 
-hid_t proc_handle_dup(Proc *p, hid_t from, hid_t to) {
+hid_t proc_handle_dup(Proc *p, hid_t from, hid_t to, int flags) {
 	Handle *fromh, **toh;
 
-	if (to < 0) {
-		to = proc_find_free_handle(p, 0);
+	if (to < 0 || (flags & DUP_SEARCH)) {
+		to = proc_find_free_handle(p, to);
 		if (to < 0) return -EMFILE;
 	} else if (to >= HANDLE_MAX) {
 		return -EBADF;
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index bf5db69..f473124 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -129,10 +129,9 @@ Proc *proc_next(Proc *p, Proc *root);
 hid_t proc_find_free_handle(Proc *proc, hid_t start_at);
 Handle *proc_handle_get(Proc *, hid_t);
 hid_t proc_handle_init(Proc *, enum handle_type, Handle **);
-hid_t proc_handle_dup(Proc *p, hid_t from, hid_t to);
+hid_t proc_handle_dup(Proc *p, hid_t from, hid_t to, int flags);
 static inline void proc_handle_close(Proc *p, hid_t hid) {
-	// TODO test
-	proc_handle_dup(p, -1, hid);
+	proc_handle_dup(p, -1, hid, 0);
 }
 
 /* Gets a handle and removes the process' reference to it, without decreasing the refcount.
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 03d9ef1..1e75f9d 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -177,8 +177,7 @@ fail:
 }
 
 hid_t _sys_dup(hid_t from, hid_t to, int flags) {
-	if (flags != 0) SYSCALL_RETURN(-ENOSYS);
-	SYSCALL_RETURN(proc_handle_dup(proc_cur, from, to));
+	SYSCALL_RETURN(proc_handle_dup(proc_cur, from, to, flags));
 }
 
 static long simple_vfsop(
diff --git a/src/shared/include/camellia/flags.h b/src/shared/include/camellia/flags.h
index 5ff9f10..f4c54fe 100644
--- a/src/shared/include/camellia/flags.h
+++ b/src/shared/include/camellia/flags.h
@@ -12,6 +12,7 @@
 
 #define FSR_DELEGATE 1
 
+#define DUP_SEARCH 1
 
 #define OPEN_READ 1
 #define OPEN_WRITE 2
diff --git a/src/user/lib/fcntl.c b/src/user/lib/fcntl.c
index 89412a5..b2d8685 100644
--- a/src/user/lib/fcntl.c
+++ b/src/user/lib/fcntl.c
@@ -1,6 +1,9 @@
 #include <bits/panic.h>
+#include <camellia.h>
+#include <camellia/syscalls.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <stdarg.h>
 
 #include <stdio.h>
 
@@ -11,7 +14,15 @@ int open(const char *path, int flags, ...) {
 }
 
 int fcntl(int fd, int cmd, ...) {
-	(void)fd; (void)cmd;
-	_klogf("failing fcntl(%d)", cmd);
-	return errno = ENOSYS, -1;
+	va_list argp;
+	va_start(argp, cmd);
+	if (cmd == F_DUPFD) {
+		int to = va_arg(argp, int);
+		va_end(argp);
+		return _sys_dup(fd, to, DUP_SEARCH);
+	} else {
+		va_end(argp);
+		_klogf("failing fcntl(%d)", cmd);
+		return errno = ENOSYS, -1;
+	}
 }